Git.pm: Make _temp_cache use the repository directory

Update the usage of File::Temp->tempfile to place the temporary files
within the repository directory instead of just letting Perl decide what
directory to use, given there is a repository specified when requesting
the temporary file.

This is needed to be able to fix git-svn on msys as msysperl generates
paths with UNIX-style paths (/tmp/xxx) while the git tools expect natvie
path format (c:/..). The repository dir is stored in native format so by
using it as the base directory for temporary files we always get a
usable native full path.

Signed-off-by: Marten Svanfeldt <developer@svanfeldt.com>
Acked-by: Eric Wong <normalperson@yhbt.net>

perl/Git.pm

@@ -961,9 +961,7 @@ issue.
 =cut
 
 sub temp_acquire {
-	my ($self, $name) = _maybe_self(@_);
-
-	my $temp_fd = _temp_cache($name);
+	my $temp_fd = _temp_cache(@_);
 
 	$TEMP_FILES{$temp_fd}{locked} = 1;
 	$temp_fd;
@@ -1005,7 +1003,7 @@ sub temp_release {
 }
 
 sub _temp_cache {
-	my ($name) = @_;
+	my ($self, $name) = _maybe_self(@_);
 
 	_verify_require();
 
@@ -1022,9 +1020,16 @@ sub _temp_cache {
 				"' was closed. Opening replacement.";
 		}
 		my $fname;
+
+		my $tmpdir;
+		if (defined $self) {
+			$tmpdir = $self->repo_path();
+		}
+
 		($$temp_fd, $fname) = File::Temp->tempfile(
-			'Git_XXXXXX', UNLINK => 1
+			'Git_XXXXXX', UNLINK => 1, DIR => $tmpdir,
 			) or throw Error::Simple("couldn't open new temp file");
+
 		$$temp_fd->autoflush;
 		binmode $$temp_fd;
 		$TEMP_FILES{$$temp_fd}{fname} = $fname;